Both iPhone 15 pro max and brand new series 9 watch overheating. Anyone else?

Let’s define “overheating”. If an iPhone overheats it shuts down so it can’t be used, and displays a message saying it must cool down before it can be turned on, and it will probably be unusable for an hour or so. If you are seeing this it is a hardware problem and you should contact Apple support: 

• Click on “Support” at the top of this page
• Go to Contact Official Apple Support

Note that both of the above have options to receive a callback or chat

If you are not seeing this your phone has not overheated. However, if you fast charge your phone may pause charging at 80% and display a message saying that charging has paused, and will resume when the phone cools down. This is NOT overheating, and is normal when fast charging. It also won’t prevent you from using any app you have on your phone.

Also, some apps that use a lot of energy or that use cellular data rather than Wi-Fi can cause the phone to run warmer.

A watch worn overnight that loses 25% is about right, it may even be a little low. It is MONITORING your sleep; that means it is always awake and running code, which uses energy.

For your iPhone issue, what troubleshooting have you done? Apple isn’t acknowledging a problem because there isn’t any, it is most likely something you or your apps are doing. As a start, do you use VPN? That is guaranteed to slow all communications to about 25% of available bandwidth.

How about any antivirus apps, or apps that claim to improve the performance of your phone? They can improve the cash flow of the app sellers while actually slowing down the phone with no benefit

Sometime due to to use third party chargers or due to summer season its happening